Sustained growth is defined as growth in both revenues and profits over a extended period of time. Evidence shows that relatively few firms generate sustained, profitable growth. For example, normally only one in three businesses that make Inc. magazine’s list of the 500 fastest growing private firms in America repeats the following year. In addition, a recent study found that only 3 percent of all firms are “gazelles” or rapid growth firms at any given time. Still, these firms are important to the economy and account for nearly all new private sector job and sales growth. As a result, studying firm growth is important to help individual firms understand how to achieve sustained growth and for a national economy.